The control of vehicular traffic often requires that certain lanes be closed to traffic and that traffic be redirected to other lanes temporarily during peak traffic hours or as a result of repair work being done. Control can be accomplished by setting warning and redirection markers by hand in the roadway but this method suffers from the disadvantages of requiring a substantial implementation time and posing hazards to the personnel placing the markers.
An automatic system of raising traffic control devices up from storage positions beneath the pavement in response to remote control signals is much more desirable. Pneumatic devices, such as those disclosed in U.S. Pat. Nos. 3,530,775 and 3,447,429, have been used but require close clearance tolerances within their construction to prevent excessive air leakage and are also subject to problems of contamination by dirt, sand, ice, snow, oil, and other materials often found on the roadway. The installation of pneumatic lines in the road is also costly and time consuming.
An improved traffic control device operated mechanically by remote control was disclosed in U.S. Pat. No. 3,963,363 to Roper, which is hereby incorporated by reference herein. The control device is attached to a follower which is engaged in the thread of a screw member caused to rotate by a remote signal, thus affecting the elevation of the control member above its storage position flush with the ground.
It would be a great advance in traffic control technology if a pop-up traffic control device similar to the one disclosed in the patent to Roper could be provided with the following features: (1) a system of sealing the device so that the interior of the storage chamber is not contaminated by foreign matter from the outside; (2) a removable tube connector system so that the traffic marker can be changed easily; (3) a modular collar with integral electrical connector; (4) a unit for signalling the up-or-down status of the device; (5) a heating unit component; (6) a slope adjustment device; (7) a lubrication and brush device; (8) a lighting unit; (9) a watertight assembly; and (10) a variable-speed feature.